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BLOCKING HIGH BREAKS DOWN

May 7, 2012 6:31 PM

Well, what a weekend in St. John's and across parts of the NE Avalon and
even up the Northeast Coast of Newfoundland. At YYT, dozens of delays,
cancellations and flights diverted. It was Friday, just before Noon when the Fog
ramped up and for the next 3 days it was pea soup thick in parts of Metro. In the end, we
had 49 hours with visibility under 800 feet and about 60 hours with visibility
under 1 km. But it wouldn't be Spring if we didn't have a few days of R-D-F
right? Right?

Here are the main points for the next few days...

-That NE wind onshore flow setup, is slowly breaking down, as the same
blocking Greenland High, actually sinks South and clears us out over the next 24
hours or so!

-Winds will continue in from the Northeast tonight and through
Tuesday along the Northeast Coast of the Island, as a result, we'll see fog
patches developing again across much of Northeastern Newfoundland tonight. However things will clear through the day on Tuesday.

-A solid Tuesday across most of Labrador as well, however watch for Rain to
move into Lab West on Tuesday afternoon and spread into Eastern Labrador on
Wednesday.

-Wednesday is the day of change across the
Island. Winds will finally become Southwesterly ahead of a system moving
in and temperatures will be on the rise.

-However Wednesday and into Thursday, that system off to our Southwest will
finally start to move into Newfoundland, with clouds and showers.

-Again, the good news, despite the increasing clouds, showers & even rain for some. Temperatures will be into the double digits and even teens for many across the Island Wednesday through Friday.

-This will be a system to watch for the West & Southwest
Coast this week. From Wednesday through Friday, some forecast models are
flirting with up to 50+ mm of Rain for parts of Western and Southwestern
Newfoundland. The GEM Canadian model below, is one that supports this idea. I'll keep you posted on this.

-And yes, it's still Spring in NL. There's a good chance of seeing Snow
mixing in along the Northern edge of this system. You folks in Labrador, could
see some of the white stuff, late Wednesday into Thursday and even into Friday.

LONG RANGE

Some good news. Based on the long range forecast models, it appears that the "Greenland Block" setup, shouldn't be re-appearing any time soon. Both the long
range European & American forecast models are leaning towards a more West to
East setup through next week. The latest NOAA outlook for the NAO (North
Atlantic Oscillation) also shows consensus that we are now coming out of
the negative NAO phase (which promotes blocking patterns) and into a more
neutral, or even positive phase into next week.